Abstract Body: Anthracycline cardiotoxicity is primarily attributed to injury in mature cardiomyocytes, yet whether chemotherapy promotes persistent changes in earlier stem-cell states remains unclear. We tested whether transient, sub-cytotoxic doxorubicin (Dox) exposure induces a naive-associated transcriptional state in human induced pluripotent stem cells (hiPSCs), thereby altering downstream cardiomyocyte differentiation and maturation. Using a Dox-adapted model (D50-hiPSC), we observed marked structural remodeling, including reduced cell size, increased nucleus-to-cytoplasm ratio, and reduced morphological heterogeneity by deep-learning-based segmentation. Despite this remodeling, D50-hiPSCs maintained stemness features, with increased SSEA4 (~2.8-fold, p=0.0001), NANOG (~1.8-fold, p=0.02), and OCT4 (~1.6-fold, p=0.0006). Bulk RNA-seq revealed broad transcriptional divergence in D50-hiPSCs, with 4,033 differentially expressed genes (fold change ≥2, FDR<0.05; 1,652 upregulated, 2,381 downregulated), characterized by induction of naive-associated pluripotency genes (DAZL, APELA, ESRRB, TFCP2L1), suppression of lineage-specifying regulators (TBXT, GATA4, SOX17), and enrichment of pathways regulating pluripotency, PI3K-Akt/TGF-beta signaling, and ECM-receptor/focal adhesion. Although D50-hiPSCs retained the ability to form beating cardiomyocytes, day-7 hiPSC-CMs showed delayed early contractile maturation, including prolonged time-to-peak contraction (1.06±0.20 s vs 0.85±0.05 s, p=0.0001), slower decay to 30% baseline (1.51±0.13 s vs 1.17±0.06 s, p=0.0001), and prolonged 90% decay time (2.03±0.21 s vs 1.81±0.27 s, p=0.0001). These findings support a model in which transient chemotherapeutic stress imprints a naive-associated transcriptional state in hiPSCs with long-term consequences for early cardiomyocyte functional maturation, highlighting a developmental component of anthracycline cardiotoxicity.